Field
The following relates to approaches to scheduling computation in multithreaded processors or groupings thereof, and in a more particular aspect, to scheduling for graphics processors with clusters of SIMD computation units.
Related Art
Parallel computation paradigms present theoretical possibilities to continue acceleration of processing computation workloads. However, taking full advantage of parallel processing is challenging. Approaches to increased parallelism that present a comparatively low burden on programmers (such as SIMD processors) can increase parallelism to some extent, and work better on some workloads than others. Other approaches to parallelism, such as multithreading require more intensive coding practices, and present other overhead, such as context switching logic.
Examples of workloads than benefit from further development of approaches to parallel processing comprise graphics processing, and in a more particular example, ray tracing of 3-D scenes to render high quality 2-D images, such as photo-realistic 2-D images. Ray tracing is known to produce photo-realistic images, including realistic shadow and lighting effects, because ray tracing can model the physical behavior of light interacting with elements of a scene. Ray tracing usually involves obtaining a scene description composed of geometric shapes, which describe surfaces of structures in the scene, and can be called primitives. A common primitive shape is a triangle. Objects can be composed of one or more such primitives. Objects each can be composed of many thousands, or even millions (or more) of such primitives. Scenes typically contain many objects, leading to scenes of tens or hundreds of millions of primitives. Resolution of displays and the media to be displayed thereon continue to increase. Ray tracing requires repeating a few calculations many times with different data (e.g. intersection testing), as well as executing special purpose code (“shading”) for identified ray intersections.